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UNITED STATES PATENT OFFICE.

CHRISTIAN l-I. ROSS, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE DAUCHY IRONIVORKS, OF SAME PLACE.

VAU LT-LIG HT.

SPECIFICATION forming part of Letters Patent No. 410,380, datedSeptember 3, 1889.

Application filed April29, 1889. Serial No.309,088. (No model.)

T0 all whom it' may concern:

Be it known that I, CHRISTIAN ll. Ross, a citizen of the UnitedStates,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new'and useful Improvement in Vault-Lights, which isfully set forth in the following specification, refer ence being had tothe accompanying drawings, in wl1ich r Figure 1 represents a plan viewof a construction embodying my invention, portions thereof being brokenaway to show the construction; Fig. 2, a sectional view taken on theline l l of Fig. l; Fig. 3, a bottom plan view of one of the glassesdetached, and Fig. 4 an elevation of the same.

Like letters refer to like parts in all the figures of the drawings.

Myinven tion relates to vault-lights, and has for its object to provideaconstruction whereby the glasses or lights proper may be caused to fitsnugly within the light-holes provided for them in the cast bedplate orframe.

In that class of vaultfcovers to which my present invention relates aniron base-plate or frameis cast with circularlight-holes,within whichthe circular glasses are intended to fit with sufficient snugness toprevent their turning or slipping, being afterward secured by a suitablecement or other similar means. These circular light-holes are frequentlyirregular in outline, owing to imperfections in the casting arising fromvarious causes, and when this is the case it is obvious that thecircular glasses will not lit within them in case the irregularityreduces the diameter at any point. This necessitates in practiceexpensive mechanical manipulations in truing the light-holes to permitthe introduction of the glasses. It is the object of my presentinvention to overcome these objections and to produce a glass which willadapt itself to the irregularities of the light-holes, so as to have alateral bearing at three or more points to prevent its slipping orrotating, thereby doing away with the necessity of truing thelight-holes, While at the same time a snug fit is obtained.

I will now proceed to describe a construction in which my invention ispractically carried out in one form, and will then particularly pointout in the claims those features b v Letters Patent.

In the drawings, A represents the bed plate or frame, which, ashereinbefore stated, is of cast-iron, provided with t-he lightholes a'.Each of these lght-holes a, is provided near its lo :ver portion with aninternally-projecting circular ledge or flange ct', upon which the glassrests and is supported vertically.

The glasses are represented at B, and are circular in form, but of adiameter somewhat less than the main diameter of the light-holes a,although of a greater diameter than the contracted portion of theselight-holes, caused by the ledge or flange a', so that when in po sitionthey will rest upon the said ledge or flange and close the light-holes,as shown in Figs. l and 2. These glasses are preferably provided withthe usual should er b, to enable the cement to hold them more firmly inposition.

Extending radially outward from the body of the glass B are a series ofprojections B', of such length that the total diameter of the glass,measured through these projections, will be equal to the diameter of thelight-hole a, or, more properly speaking, to the diameter which itshould have if properly constructed. In the present instance I haveshown six of these projections; but it is obvious that their number maybe varied as desired, and that their form may be other than that shown.Their height is preferably equal to the height of the portion of theglass below the shoulder b.

I) represents a fllling of cement or other suitable material, which isapplied after the glasses B are placed in position, and finished oiabout level with the top of the glasses to make la smooth surface, thesaid cement serving to hold the glasses firmly in one position andpresent a good walking-surface for pedestrians.

In placing' the glasses B in position it will be seen that if thelight-holes a are properly constructed the glasses B will fit snuglytherein, having a lateral bearing all around against the side Wall ofthe said holes. It', however, the said holes are irregular, as isfrequently the case, the glass maybe so turned that those IOO portionsthereof which are not provided with the projections B willl come'opposite' the reentrant portions of the bed-plate A, which wouldotherwise'so diminish the diameter of the light-hole as to preventinsertion of the glass, and when so turned the glass may be placed inposition in the hole, notwithstanding the irregularity of this latter,so as t0 rest properly upon the flange or ledge a and have a lateralbearing all around. lt will thus be seen that the expensive operation oftruing the holes is done awayT with, thereby considerably reducing thecost of the article.

The advantage of having the glass iit prop erly within the bed-plate andframe, so as to have a downward bearing and a lateral bearing upon theiron or" which it is composed, lies in the fact that in this positionthe force of any blows coming upon the glass is resisted by the iron andnot by the cement, which latter would chip or crumble under such blows,and would soon loosen the glass, causing it to become displaced orgiving rise to a leakage in the vault-cover, These advantages are ofcourse obtained without anyincrease of expense by the construction whichI have devised.

It is obvious that various modifications in the details of constructionmay be made with- 30 out departing from the principle of my invention,andv I therefore do not wish to be understood as limiting myself.strictly to the vprecise details hereinbefore described, and vshown inthe drawings.

Having thus described my invention, whatl claim as new, and desire tosecure by Letters Patent; is-f.

l. The combination, with the bed-plate A, having light-hole a, providedwith circular ledge or' ange a', of the glass B, having a body port-ionof less diameter than the main diameter of the light-hole, but greaterthan its contracted diameter, said glass being provided at its marginwith radial projections to bear against the side wall of the light-hole,substantially as and for the purposes speciied.

2. The combination, with the bed-plate A, having light-hole a, withflange orledge a', of the glass B, having a body port-ion of vadiameter" less than the main diameter of the lighthole a, but greaterthan its reduced diameter, said body portion being provided with radialprojections B', to bear against the side wall of the light-hole, andshoulder b, and the iilling D, of cement or the like, substantially asand for the purposes specified.

' CHRISTIAN H. ROSS.

Witnesses;

ALICE MoIvER, Birma MILLER..

